Is Customer Service Agent and the Customer two different personas or different roles?

Are 'Personas' and 'Roles' different in every scenario?

Although i did my reading about roles and personas, im a bit confused about this topic with the context i'm working on.

Scenario - One day Bruce(Customer) finds out his water heater is broken and calls XYZ company to get it fixed. John(Customer service agent) receives the call and assigns Bob(Technician) for to install a water heater.

John, Bruce and Bob are these 3 personas? or are they considered as 3 different user roles who interact with XYZ service?